With the development of wireless communication technologies and the constant increase of related services, mobile phones have become indispensable tools in the daily life, which results in a stronger demand on the usage security of mobile phones. A Subscriber Identity Module (SIM) card and other storage media are used to identify the identification information and other private information of a user in the mobile phone. Therefore, all the information stored in the mobile phone will be exposed once the mobile phone is lost.
At present, there are mainly two methods for the information security of the mobile phone. One is to encrypt user data, namely, user information is encrypted by using a character string input by a user as a key according to a set encryption algorithm and then stored. The other one is to prevent the mobile phone from stolen, namely, an external device matched with the mobile phone is adopted and wireless communication is maintained between the external device and the mobile phone so that the external device can remind the user when the wireless communication is interrupted as the distance between the mobile phone and the device exceeds a certain distance.
For the first method, limited by the performance of a mobile phone processor, the encryption algorithms which can be supported by the mobile phone are often very simple and most of them are public; moreover, the key is stored in the mobile phone and thus can be decrypted very easily, so the privacy of the user still cannot be protected effectively. For the second method, the mobile phone, which is a common device, is often exposed, so the risk of being stolen is very high; in addition, an anti-theft device for the mobile phone cannot give a precise reminder if the user information is stolen deliberately.